What Contributions Do Spiders Make to Ecosystems and to Humans?

Spiders have long carried a reputation that evokes fear, yet from a biological perspective they are in fact among the most underestimated organisms on Earth. More than 53,000 spider species have been formally described worldwide, while the actual number of species is estimated to exceed 120,000. Their diversity is astonishing. Some species measure less than half a millimeter in body length, whereas giant tarantulas may reach leg spans of up to 30 centimeters. Because spiders occur almost everywhere and possess remarkable adaptability, the services they provide within ecosystems are extensive. They help regulate pest populations, influence nutrient cycling, provide habitat structures, and serve as food resources for other organisms. Despite these important roles, their contributions are frequently overlooked, often dismissed because spiders trigger fear in many people. Yet if we wish to understand how natural systems function—or even draw inspiration from nature to solve human challenges—spiders cannot be ignored.

The contributions of spiders can be divided into four main categories: provisioning, regulating, supporting, and cultural（Image source：Cardoso P et al. (2025)， CC BY 4.0 ）

The feature for which spiders are best known is silk. Spiders possess complex silk gland systems that may include seven or eight distinct gland types, such as the major ampullate gland, minor ampullate gland, flagelliform gland, aggregate gland, aciniform gland, tubuliform gland, and pyriform gland. Each gland produces silk with specific mechanical properties and ecological functions. The protein structure of these silks is extraordinarily sophisticated. For instance, the protein MaSp1 found in major ampullate silk combines exceptional strength with elasticity, making it one of the toughest materials found in nature.

Spider silk gland system（Image source：Jane G and Kuria KP. (2021)， CC BY 4.0 ）

For many years researchers have attempted to produce spider silk proteins at industrial scales. However, spiders are difficult to rear in large numbers because of their territorial and cannibalistic behavior. As a result, scientists have increasingly turned to genetic engineering, inserting spider silk genes into organisms such as bacteria, yeast, or even silkworms to produce silk proteins. In one notable example, genetically modified silkworms were able to spin fibers whose toughness surpasses that of Kevlar. In parallel, researchers have established the Silkome database, which compiles protein sequences and properties of spider silk from thousands of species. With these datasets, artificial intelligence can now analyze silk structures and design entirely new high-performance materials. Beyond the fibers themselves, the adhesive components of spider silk are also attracting attention. Their durability, effectiveness, and environmentally friendly properties make them promising templates for the development of sustainable adhesives.

Spider morphology has also inspired a wide range of engineering innovations. Spider legs extend through hydraulic pressure generated by body fluids, a mechanism that has influenced mechanical and robotic design. In the Moroccan desert, the spider Cebrennus rechenbergi can roll rapidly across sand dunes, and its unusual locomotion has inspired robots capable of rolling across sandy terrain at high speed. Spider adhesive foot hairs have inspired reversible adhesion technologies, while the structural colors found in some species have guided the development of pigment-free coloration materials for electronic displays and textiles. Even more remarkable are the slit sensilla found on spider bodies. These crack-like sensory structures detect minute vibrations and have inspired nanoscale acoustic sensors that could function as highly sensitive microphones or vibration detectors. Certain desert spiders, such as Leucorchestris arenicola, are able to navigate at night without relying on sunlight, odor cues, wind direction, or obvious landmarks. Understanding how they accomplish this may help guide the development of navigation systems for spacecraft or autonomous vehicles operating in extreme environments.

Spider venom represents another remarkable natural resource. The venom of a single species may contain hundreds to thousands of compounds, many of which are highly stable neurotoxic peptides that target specific ion channels or receptors with remarkable precision. Research has revealed that some of these toxins show potential for treating pain, neurodegenerative diseases, cancer, infections, and even malaria. One example comes from the Australian funnel-web spider Hadronyche infensa. Its venom contains a peptide known as Hi1a that can protect heart and brain tissue from damage caused by ischemia. This compound has demonstrated potential for improving outcomes in heart transplantation and is currently being developed toward medical applications. In addition, antimicrobial peptides found in spider hemolymph are considered promising candidates in the fight against antibiotic-resistant bacteria.

Spider biomaterials and bioactive compounds hold great potential for technological innovation; their body structures, behavioural strategies, and secretions provide a rich source of inspiration（Image source：Cardoso P et al. (2025)， CC BY 4.0 ）

Spiders interact with human society in many ways that often go unnoticed. In agricultural systems, they act as natural suppressors of pest populations. Experimental studies in orchards of apple and pear trees have shown that increasing spider abundance can significantly reduce populations of moths and pear psyllids, ultimately increasing fruit yields. Some spiders remain active even during winter and can continue hunting pests at temperatures below freezing, suppressing pest populations before the next growing season begins. In annual crops and greenhouse systems, although fewer studies have been conducted, spiders have also been shown to reduce early infestations of pests such as aphids. Spiders are not specialized biological control agents, but they form a crucial component of the predator networks that maintain ecological balance in agricultural landscapes.

Spiders also play a role in disease regulation. They prey upon numerous arthropods that act as vectors of human diseases, including mosquitoes, biting midges, true bugs, and ticks. Certain indoor spiders, such as the cellar spider Pholcus phalangioides, are capable of capturing large numbers of small biting flies that breed indoors. In East Africa, the jumping spider Evarcha culicivora shows a remarkable preference for feeding on blood-engorged malaria mosquitoes. Some wolf spiders have been shown to reduce tick activity, indirectly lowering the risk of disease transmission. In the context of invasive species, spider predation can also have ecological benefits. In Portugal, for example, the ant-eating spider Zodarion atlanticum preferentially preys on the invasive Argentine ant Linepithema humile.

At the level of ecosystem functioning, spiders influence processes such as nutrient cycling. On forest floors, leaf litter decomposition is accelerated by small arthropods such as springtails, which shred organic material. Spiders prey on these organisms, meaning that their presence can either accelerate or slow decomposition depending on ecological conditions. In grassland ecosystems, actively hunting spiders and ambush-type spiders can influence the behavior of herbivorous insects. These behavioral changes ripple through food webs, altering plant productivity and even affecting carbon and nitrogen cycling in soils.

Spiders themselves are also a vital food source for many animals. Birds, amphibians, reptiles, mammals, and even fish consume spiders as part of their diets. Parasitic organisms also depend on spiders for their life cycles. Certain parasitoid wasps manipulate spiders into constructing modified webs that protect the developing wasp pupa. Spider nests and abandoned webs create microhabitats for other organisms, including mites, pseudoscorpions, and small insects. Some birds even collect spider silk as a material for building their nests.

The ecosystem services provided by spiders run far deeper than most people realize. They inspire advances in materials science, serve as silent guardians in agricultural landscapes, and help drive the ecological processes that sustain natural systems. Understanding spiders therefore represents more than an appreciation of an often-misunderstood group of animals. It offers a pathway toward understanding how nature functions—and how human societies might draw inspiration from it to develop future technologies and solutions. When we begin to reconsider these animals that have long been feared or overlooked, we come one step closer to understanding the intricate workings of the natural world.

Author: Shui Ye-You

Reference:

Cardoso P et al. (2025). Ecosystem services provided by spiders. Biological Reviews.

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